Combination Vehicles - Quiz Sample #2, 15 questions
What statement best explains “crack the whip effect”?
When you make a quick lane change or sudden movement with your steering wheel, the rear trailer tends to swing out. The force of the rear trailer becomes amplified, causing it to roll over (rearward amplification).
Your trailer is half full and the cargo is loaded in the front of the trailer. When you make a sudden steering wheel movement cargo will tend to forcefully slide to the back of the trailer, forcing the trailer to roll over.
When you make a quick lane change or sudden movement with your steering wheel, the tractor tends to rock and sway. The velocity of the rearmost trailer forces the tractor to roll over before the trailer.
Which type of truck-trailer combination has the best chance of the “crack the whip” rollover?
A single tractor-trailer.
A tractor pulling 3 trailers.
A tractor pulling 2 trailers.
Which trailers are most likely to get stuck on railroad tracks? (Select three)
Lowboy trailers. A low slung unit.
Possum-belly livestock trailers. A low slung unit.
Tandem axle tractor pulling a flatbed.
Single axle tractors pulling a short trailer. A low slung unit.
Where should the tractor be when you inspect landing gear after uncoupling the trailer?
With the tractor frame under the trailer.
Completely cleared from the trailer.
With the fifth wheel directly beneath the kingpin.
Under good driving conditions, you should leave at least one second of space between your vehicle and the vehicle ahead for every ____ feet of your vehicle’s length.
10
20
30
The safest way to make a turn without entering another traffic lane is:
You should turn wide before you start the turn.
You should turn wide as you complete the turn.
You should not make a turn and move to another place where you can make a turn without crossing other lanes.
In general, the higher your truck’s center of gravity, the:
Easier it is to turn around corners.
More stable it is when turning.
Easier it is to turn over.
If the service line comes apart while you are driving a combination vehicle, but the emergency line stays together, what will happen right away?
The trailer’s tank will exhaust through the open line.
The emergency trailer brakes will come on.
Nothing is likely to happen until you try to apply the brakes.
Glad hands are used to connect the:
Electric lines from the tractor to trailer.
Kingpin from the trailer to the locking jaws of the fifth wheel.
Service and emergency air lines from the truck to the trailer.
A driver crosses the air lines when hooking up to an old trailer. What will happen?
The hand valve will apply the tractor brakes instead of the trailer brakes.
If the trailer has no spring brakes, you could drive away but you wouldn’t have trailer brakes.
The brake lights will come on when the brake pedal is pressed.
When driving a set of doubles it is necessary to close which shut-off valve in the last trailer?
Front.
Back.
Middle section.
Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the:
Air compressor to unload instead of pumping air.
Emergency trailer brakes to come on.
Trailer supply valve to open.
How much space should be between upper and lower fifth wheel after coupling?
Just enough to see light through it.
About 1/4 inch.
None.
If the brakes are not released when you pushed the trailer air supply valve you should:
Check air line connection.
Cross the air lines.
Check electrical cable.
You have pushed the trailer air supply valve. You shouldn’t back a tractor under a trailer until the whole air system is:
At normal pressure.
Empty.
Between 60 and 80 PSI.
You are coupling a tractor to a semi-trailer. You have connected the air lines. Before backing under the trailer you should:
Supply air to the trailer system, then pull out the air supply knob.
Pull ahead to test the glad hands connections.
Make sure that the trailer brakes are off.
After you have coupled the trailer you should have to raise the landing gear by using:
Low gear.
Intermediate.
High gear.
When connecting the glad hands press the two seals with the coupler together at what degree to each other?
45 degrees.
90 degrees.
180 degrees.
The trailer is coupled to the tractor and the trailer landing gear is up. Before driving, make sure:
There is enough clearance between the upper and lower fifth wheels.
There is enough clearance between the tractor frame and the landing gear.
The safety latch is in unlocked.
When you are uncoupling a loaded trailer lower the landing gear until it:
Reaches the ground.
Makes contact with the ground and leave the trailer off the fifth wheel.
Makes firm contact with the ground.
When coupling, the proper position of the fifth wheel is:
Level with the ground.
Tilted down toward the end of the tractor.
Tilted up toward the end of the tractor.
Air and electrical lines from the tractor to the trailer should be:
Resting on the frame of the tractor.
Pulled tight with very little slack.
Secured, but with enough slack for turns.
When backing a tractor under a trailer you should:
Do it quickly to ensure that the kingpin is locked into the fifth wheel.
Always use lowest reverse gear.
Always approach the trailer at a slight angle.
Compared to a straight truck or bus there are ____ things to inspect in combination vehicles.
Fewer.
The same number.
More.
While checking if the tractor is securely coupled to the trailer, the landing gear should be:
Fully lowered.
Fully raised.
Slightly raised.
After you lock the kingpin into the fifth wheel, you should check the connection by pulling:
Forward 50 feet, turning right and left.
The tractor ahead gently with the trailer brakes locked.
The tractor ahead sharply to release the trailer brakes.
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